IC14 Flashcards
Role of Vit D
helps Calcium to be absorbed from GIT
What happens when there is low Ca
PTH secretion will incr, causing incr bone resorption and reabsorption of Ca in renal distal tubule
At clinical doses, PTH analogues act more like a _____
anabolic agent
Osteoclast stimulates bone____
resorption
Osteoblast stimulates bone___
growth
RANKL and sclerostin are produced by ____
osteocyte
Role of sclerostin
Sclerostin binds to osteoblast -> inhibit WNT signalling -> repress dy/dx of osteoblast & ability to grow new bone
Role of RANKL
Stimulates osteoclast to break down bone
Example of RANKL inhibitor
Denosumab
Role of anti-resorptive agents
Blocks bone breakdown
Examples of anti-resorptive agents
- Bisphosphonates
- denosumab
- oestrogen
- calcitonin
MOA of bisphosphonates
Slow bone loss by incr osteoclast cell death
In what situation is bisphosphonate use > 5 years appropriate?
10yr total fracture risk > 20% OR prior vertebrae fracture
MOA of denosumab
Human mAb Inhibits RANKL -> prevents osteoclast development
Administration of denosumab (route & frequency)
SC injection every 6 months
What to co-administer with denosumab
1000mg Ca +/- (min) 400 IU vit D daily
Discontinuation of denosumab may cause ___
Risk of spinal column fractures
Oestrogens MOA
Helps maintain bone density
What is raloxifene
Selective oestrogen receptor modulator
MOA of raloxifene
Mixed oestrogen receptor agonism and antagonism
-> Mimics effects of oestrogen on bone density in postmenopausal women.
Risk of using oestrogen therapy
- Incr risk of breast cancer
- Incr risk of blood clots
What is calcitonin and how is it secreted
Peptide hormone secreted by parafollicular cells of thyroid gland
Dosage forms for calcitonin
IV/ IM/ SC/ nasal spray route
Examples of anabolic agents
- romosozumab
- parathyroid hormone therapy
MOA of romosozumab
Humainised mouse mAb -> inhibits sclerostin activity -> incr bone formation & decr bone resorption
Administration of romosozumab
SC injection once a month
When is romosozumab used
For women at high fracture risk / those who failed or intolerant to other therapies
Example of Parathyroid hormone similars
teriparatide
Administration of Parathyroid hormone similars
Once daily SC injection
Max tx duration for parathyroid hormone similars
24 months
IV zoledronate administration
Once a year
Oral alendronate administration
Once a week
Oral risedronate administration
Once a week or month
